SDSU Mumps Outbreak Grows to 14 Confirmed Cases, County Urges Third Vaccine Dose for Close Contacts

The mumps outbreak at San Diego State University has expanded to 14 confirmed cases and one probable case as of Sept. 30, the County of San Diego reported this week.

The County first confirmed the outbreak on Sept. 18, and the updated figures reflect data collected through the end of September.

Mumps spreads through close face-to-face contact within three feet — through coughing, sneezing, or talking — making university campuses particularly vulnerable. The County is notifying close contacts of confirmed cases about possible exposure.

For those identified as close contacts, the most effective prevention strategy is a third dose of the Measles, Mumps, and Rubella (MMR) vaccine, which boosts immunity that may have waned since childhood, according to county health officials. The booster does not protect those already infected but reduces transmission risk among contacts.

Symptoms include fever, headache, earache, and swelling of the salivary glands resulting in jaw tenderness. Severe complications are rare but can include meningitis, decreased fertility, and permanent hearing loss. There is no specific treatment for mumps; isolation during symptoms reduces spread.

SDSU is coordinating with the County and the California Department of Public Health on educational campaigns, purchasing additional vaccine doses, and encouraging vaccination among close contacts. The university maintains a dedicated mumps outbreak webpage with FAQs.

Mumps outbreaks on university campuses often last several months, the County noted.